This invention pertains to a well drilling assembly and method and more particularly to improved clamping means for supporting a length of drilling sections of pipe while manipulating the drilling sections.
Heretofore, in well drilling operations using a bit applied to an end of a first section of pipe while rotating the pipe to drill a hole into the earth, a sequence of pipe sections are added so that the combined group of sections will rotate together further and further into the earth. In order to drive the pipe, according to one arrangement, a hand-held motor is coupled to the top of the pipe. As each short section (on the order of five feet) enters the ground the motor must be de-coupled from the uppermost section and a subsequent section of pipe connected. At that point, the top end of the outermost end of pipe is disposed at least five feet above the ground while efforts are made to connect the motor to the upper end of the newly added pipe section.
An alternative arrangement is to first couple the newly added pipe section to the motor and then to couple the lower end of the newly added section to the upper end of the pipe column. In either event it is necessary to manhandle a relatively heavy motor up in the air at least shoulder high or better and this becomes quite tiresome in the course of a day's drilling. Also, at this time it is necessary to hold the drilling sections spaced from the bottom of the drilled hole.
Further, drilling of the kind described involves further problems such as insuring against the binding action of the earth about the pipe as the pipe stops rotating. Accordingly, it has been found useful to lift the pipe column upwardly somewhat out of the hole in order to keep the bottom section from becoming locked in the material in the hole. Lifting the pipe upwardly adds further to the height to which the motor must be lifted in order to couple it to the top of the newly added section.